91ɫƵ

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Radiology
Andrew S. Nencka, PhD

Andrew S. Nencka, PhD

Associate Professor; Associate Director, Center for Imaging Research (CIR); Section of Imaging Research, Division of Imaging Sciences

Locations

  • 91ɫƵ
    Department of Radiology

Contact Information

Education

PhD, Biophysics, 91ɫƵ, Milwaukee, WI, 2009
BS, Physics & Mathematics, Marquette University, Milwaukee, WI, 2004

Research Experience

  • Data Interpretation, Statistical
  • Diffusion Tensor Imaging
  • Echo-Planar Imaging
  • Image Enhancement
  • Image Processing, Computer-Assisted
  • Machine Learning
  • Magnetic Resonance Imaging
  • Models, Statistical
  • Monte Carlo Method
  • Regression Analysis

Leadership Positions

  • Associate Director, Center for Imaging Research, 2016-Present
  • Chair, Faculty IT Committee, 2014-2016
  • Chair, Research MRI Safety Committee, 2012-Present
  • Secretary, Faculty IT Committee, 2016-2017

Research Interests

Image Acquisition Acceleration

One aspect of my research work has been to leverage the phase of acquired images, along with varying receive coil sensitivities, to further spatially encode the acquired data. With the assumption of real-valued images—an assumption often made for partial Fourier image reconstruction—this insight theoretically enables acceleration factors of 2N for an array of N coils. We have used this technology to implement a parallel slice acquisition method that simultaneously excites an array of slices with varying magnetization phase such that the magnetization phase and receive coil sensitivity profiles can be used to unalias the acquired slices. We have also used this technology to acquire and unalias accelerated single-slice images acquired with a single-channel body receiver coil.

Fast MR Relaxometry

Image acceleration techniques have enabled the development of a fast relaxometry pulse sequence, which we have named the gradient-recalled echo, asymmetric spin echo (GREASE) pulse sequence. The pulse sequence, including six echo-planar imaging readouts, two 90-degree excitation pulses, and two 180-degree refocusing pulses in each repetition, allows the computation of T1, T2, and T2* with each repetition. The acceleration techniques of GRAPPA and partial Fourier acquisition in the echo-planar imaging readouts reduce the duration of the imaging readout train so that signal decay does not eliminate the needed signal in later echoes. Thus, the relaxivity values for a single slice of 2 mm isotropic resolution can be acquired in less than 300 ms with this sequence. Further, the nearly simultaneous acquisition of the six images, the identical echo-planar imaging readouts, and the usage of the six images from each repetition for the estimation of relaxivity parameters allow the perfect coregistration of the computed maps.

Publications

  • (Sharafi A, Arpinar VE, Nencka AS, Koch KM.) Skeletal Radiol. 2025 Jan;54(1):57-65 PMID: 38767657 SCOPUS ID: 2-s2.0-85193723962 05/20/2024

  • (Johnson KA, Pawela CP, Nencka AS, Sidabras JW.) bioRxiv. 2024 Oct 13 PMID: 39416106 PMCID: PMC11482890 10/17/2024

  • (Koch KM, Nencka AS, Kurpad S, Budde MD.) J Neurotrauma. 2024 Sep;41(17-18):2125-2132 PMID: 38251658 SCOPUS ID: 2-s2.0-85190264996 01/22/2024

  • (Chu DY, Imhoff-Smith TP, Nair VA, Choi T, Adluru A, Garcia-Ramos C, Dabbs K, Mathis J, Nencka AS, Conant L, Binder JR, Meyerand ME, Alexander AL, Struck AF, Hermann B, Prabhakaran V, Adluru N.) Brain Behav. 2024 Aug;14(8):e3643 PMID: 39099405 PMCID: PMC11298711 SCOPUS ID: 2-s2.0-85200232728 08/05/2024

  • (Pahapill PA, Arocho-Quinones EV, Chen G, Swearingen B, Tomas CW, Koch KM, Nencka AS.) J Pain Res. 2024;17:1453-1460 PMID: 38628431 PMCID: PMC11020324 04/17/2024

  • (Denis C, Dabbs K, Nair VA, Mathis J, Almane DN, Lakshmanan A, Nencka A, Birn RM, Conant L, Humphries C, Felton E, Raghavan M, DeYoe EA, Binder JR, Hermann B, Prabhakaran V, Bendlin BB, Meyerand ME, Boly M, Struck AF.) Ann Clin Transl Neurol. 2023 Nov;10(11):2149-2154 PMID: 37872734 PMCID: PMC10647008 SCOPUS ID: 2-s2.0-85174616650 10/24/2023

  • (Chu DY, Adluru N, Nair VA, Choi T, Adluru A, Garcia-Ramos C, Dabbs K, Mathis J, Nencka AS, Gundlach C, Conant L, Binder JR, Meyerand ME, Alexander AL, Struck AF, Hermann B, Prabhakaran V.) Epilepsia. 2023 Sep;64(9):2484-2498 PMID: 37376741 PMCID: PMC10530287 SCOPUS ID: 2-s2.0-85164792241 06/28/2023

  • (Pahapill PA, Chen G, Arocho-Quinones EV, Nencka AS.) Neuromodulation. 2023 Jul;26(5):1009-1014 PMID: 37204362 SCOPUS ID: 2-s2.0-85159401230 05/19/2023

  • (Garcia-Ramos C, Adluru N, Chu DY, Nair V, Adluru A, Nencka A, Maganti R, Mathis J, Conant LL, Alexander AL, Prabhakaran V, Binder JR, Meyerand ME, Hermann B, Struck AF.) Cereb Cortex. 2023 Jun 08;33(12):8056-8065 PMID: 37067514 PMCID: PMC10267614 SCOPUS ID: 2-s2.0-85163480791 04/18/2023

  • (Sharafi A, Nencka AS, Koch KM.) ArXiv. 2023 May 25 PMID: 37292477 PMCID: PMC10246087 06/09/2023

  • (Panigrahy A, Schmithorst V, Ceschin R, Lee V, Beluk N, Wallace J, Wheaton O, Chenevert T, Qiu D, Lee JN, Nencka A, Gagoski B, Berman JI, Yuan W, Macgowan C, Coatsworth J, Fleysher L, Cannistraci C, Sleeper LA, Hoskoppal A, Silversides C, Radhakrishnan R, Markham L, Rhodes JF, Dugan LM, Brown N, Ermis P, Fuller S, Cotts TB, Rodriguez FH, Lindsay I, Beers S, Aizenstein H, Bellinger DC, Newburger JW, Umfleet LG, Cohen S, Zaidi A, Gurvitz M.) Journal of Cardiovascular Development and Disease. September 2023;10(9) SCOPUS ID: 2-s2.0-85172930672 09/01/2023

  • (Koch KM, Nencka AS, Klein A, Wang M, Kurpad S, Vedantam A, Budde M.) Front Neurol. 2023;14:1172833 PMID: 37273696 PMCID: PMC10236479 SCOPUS ID: 2-s2.0-85161052826 06/05/2023